This portable keychain LED alcohol breath tester is easy to use, quickly respond and resume in seconds. Keyring design: It is portable, handy and convenience to carry. How to use: 1. Press and hold the power button to warm-up. 2. When warm-up is succeed, just simple blow into the breath inhaler for 3-5 seconds. 3. Read the test result. Only Green LED light on: , the alcohol concentration level is under 0.02% BAC (0.1mg/l BRAC). Only Yellow LED light: Caution, the alcohol concentration level is 0.02% to 0.05%BAC (0.1mg/l BRAC to 0.25mg/l BRAC). Yellow LED & Red LED light both on: Danger, the alcohol concentration level is over 0.05% BAC ( 0.25mg/l BRAC). Specification: Item Type: Alcohol Breath Tester Material: PP Item Color: As Pictures Shown Battery: 2 * AAA Batteries (Not Included) Item Size: Approx. 7 x 3.5 x 2 cm / 2.8 x 1.4 x 0.8 inch Package Weight: Approx. 36 g / 1.3 oz Package Include: 1 * Keychain Alcohol Breath Tester Note: 1. After drinking, it is recommended to wait 20 minutes before testing, because alcohol takes about 20 minutes to enter the from the digestive organs, and alcohol remained in the mouth also takes time to dissipate. 2. For more accurate results, the time between each test should be three minutes. 3. Do not clean it by cleaning lotion contained and gasoline. Do not let any liquid into the machine. 4. Please allow 1-3 cm error due to manual measurement. Please make sure you do not mind before you bid.